However while SirA inhibits CsrA activity via the activation of csrB , SirA does not regulate the transcription of csrA .
No further increase in PefA expression was apparent in TS133 , thus the lack of inactivation of the SirA-regulated genes csrB and csrC produced similar effects on PefA expression .
No further increase in PefA expression was apparent in a sirA csrB csrC DfimAICDHF mutant , thus the lack of inactivation of the SirA-regulated genes csrB and csrC produced similar effects on PefA expression .